1. Field of the Invention
The present invention relates to gas turbine engines, and more particularly, to a fuel injector for such engines.
2. Description of the Prior Art
The combustion chamber of certain gas turbine engines may be an annular tube with a plurality of fuel injectors or nozzles that are spaced apart circumferentially. Each fuel injector in such an arrangement must be efficient and provide a proper distribution of an atomized fuel and air mixture in the zone surrounding the particular injector. Preferably this mixture is distributed as a conical spray. It is also important that the fuel be atomized in order to promote efficient burning of the fuel in the combustion chamber. The control of the spray cone can be effected by providing a swirl to the mixture as it leaves the injector. The swirl can be provided by deflectors or directing air jets to provide a vortex. However, such devices are often spaced apart from the actual fuel nozzles forming part of the fuel injector.
U. S. Pat. 5,579,645, issued Dec. 3, 1996 to the applicant, describes a fuel nozzle having first and second annular air passages and an annular fuel passage between the first and second air passages. The result is a conical air-fuel-air sandwich which greatly enhances the formation of atomized fuel droplets in order to improve the efficient burning of the fuel. It has been found that in some cases the spray cone formed by the nozzle is too wide and results in wall impingement. Therefore, there is a need to control the angle and pattern of the spray cone.